Rivers Run Deep
by elphabathedelirious32
Summary: River Song. River Tam. Both on the run from people who want to turn them into weapons. What could be better? River Song, 25, wakes up on Persephone in 2520, only to be ushered onto Serenity by a typically cryptic River Tam. What could go wrong? Gen.
1. Chapter 1

**A/N: I've been wanting to write a crossover involving River Song and River Tam for quite a while, and after having River Song's identity confirmed in _A Good Man Goes to War, _with the added bonus that some terrible government-type force wants to turn her into a weapon, well...too shiny to resist. I am unfortunately taking calculus this summer, so depending on how much work that turns out to be, I may or may not be able to promise regular updates. **

**Disclaimer: Moffat and Whedon own all. I own nothing. **

2520

Somewhere, somewhen in the universe, River Song is twenty-five years old today. She's twenty-five years old here and now, too, in her own personal timeline, but she's not quite sure when it is outside of that or where, and she can't remember how she got here.

Well, first there was a Time Agent and then a Vortex Manipulator (of which she is now in possession, thank you very much, it's not difficult to pick a drunk man's pocket) and then the police might have been alerted and they weren't very _nice_ and there's always the risk someone _else_ is coming after her and her DNA, too, so she ran without thinking and may have landed a little harder than she intended.

_Ow_. Her head echoes with pain like a bombed cathedral. Yes, definitely landed hard…but where? Some kind of docks from the crates and such piled around her, but what kind, sailboats or steamers or spaceships? She pulls herself to her feet and climbs atop a pile of crates. Oooh. Spaceships. Good.

"You need a ride."

River Song whirls, hand going for the knife she keeps at her hip since she lost her blaster in an unfortunate incident with some neo-Egyptian space pirates. When she sees what's behind her, she relaxes a little but not much.

A girl, a few years younger than she is, maybe more. Not more than twenty, could be fifteen. Long brown hair, skinny, in a little dress and no shoes. Not a threat, half of River Song's mind thinks, but then she remembers that she's only a curly-haired girl in short pants herself. At least she has shoes. And her knife. But the girl is either naïve or keeping a secret because she's got her head cocked and is staring at River with the innocence of a child and the deep knowing of a seer.

"Who are you?" River Song demands, forcing a note of authority into her voice. The girl only laughs, not mockingly, but with genuine pleasure.

"River," the girl says.

"What?" River Song's hand finds the knife in her pocket and grips it hard. It's never good if they know your name; either you've been here later and don't know it or they're with the people who took you before and who will never ever take you again. Not alive, anyway.

"_River_," the girl says insistently. "I'm River Tam, and you need a ride, don't you?" This is what she says out loud, this is what River Song hears. What's tumbling through her mind instead is something more akin to _Riverriver, like me, like you, you're a song and i'm a dance and you're a weapon too, aren't you, born in shining metal halls like me were there knives river like the one in your pocket in my pocket too? Don't leave home without it, never know who will want to play hide and seek on the way, Captain asks why we can't ever flow smooth, we rivers like to wind a song a dance around before we come in from the cold for the kill. _

But she's twenty now, and well enough to be pilot as well as junior doctor to Simon 'case he's hurt or stranded or worried, well enough for Jayne to have started thinking things she'd rather not have in her head but not well enough to keep them out.

"Depends on where."

"Anywhere that's not here, or the place you're running from." She sees the other River's fingers tighten on the hilt of the blade in her pocket and smiles. "Good to have a knife, but you don't need it now."

"I don't know that I won't, seeing as you seem to know all my secrets, and in my experience, little girl, that rarely bodes well."

"Little girl's not a threat."

"That's what they want you to think, but I know better."

"You're a little girl, too. Little girl lost, taken away."

"See, how do you know that?"

"I know you're running because I'm running, too." If she weren't psychic, that would have been a risk, but this River is even more lost than she; doesn't even know what planet she's on or when, let alone who's wanted. Thinks she's wanted. Anyway, won't tell. "You're right. I'm a threat. Not to you. Like you."

"What do you mean?"

"You're a weapon, too." Blithely stated.

River Song is alarmed. River Tam has begun to dance a bit, executing a graceful spin before pulling herself together.

"How do you know that?"

"Told you," the younger River says, and turns to leave. "You need a ride. Come on, if you want one knows how to run fast."

Still fingering the knife in her pocket, River Song follows.

…

Captain Mal Reynolds is annoyed, and this is not ameliorated when he sees River leading someone who is probably a passenger and definitely some kind of trouble up the ramp and into the cargo bay.

"Who's that?" he yells, running—not running, moving at a dignified, captainly, but rather brisk pace is all—down the stairs.

"Passenger," River calls offhandedly, continuing onboard.

"This dump runs fast?" the other girl says.

River grins. "Course it does. I'm the pilot."

"Who said anything about passengers? Because I didn't, Li'l Albatross, and as I recall I'm the captain of this boat. Which is _not _a dump," he adds, glaring at the intruder.

"Captain, this is River, she's running." River says nonsensically.

"I need to call your brother, get some new meds or a new pilot, Albatross?"

River rolls her eyes theatrically. "_No_," she says, and gestures toward the other girl. "Her name is River _also_. River Song."

"I never told you that," River Song says, eyes narrowed.

River giggles. "Can't run from my secret and neither can you," she says. "Part of us, got inside."

"I don't like this runnin' talk," Mal says, concerned. "Passengers runnin' from somethin' bring nothing but trouble, Albatross!" He calls the last bit out because River is walking away. "_Albatross!_"

"Good luck, Captain," she says over her shoulder. "I know you know that."

"Stay out of my head!"

"Inara said. Wasn't over the shock you knew a poem."

Laughter lingers after River disappears over the bridge. Mal heaves a deep sigh and turns to River #2, which boded well as all gorram hell.

"Can you pay?"

River reaches a hand inside her bag, feels around, grins. The Vortex Manipulator wasn't all she stole from that Time Agent. "Yes, I can."


	2. Chapter 2

Take Mal's reaction, double it twice, and you have Jayne and Simon. The two have disturbingly similar expressions of shocked horror on their faces when they catch a glimpse of Mal showing River Song around.

"Doctor," says Mal, roughly, gesturing at Simon. "Public relations," he says, gesturing at Jayne. Simon snorts and covers it, badly. Jayne swats the doctor on the shoulder with a fist.

"Ow," says Simon, "Hey!"

Kaylee hears the voices and her lover's cry of pain, mild though it was, and emerges from a corridor, covered in her usual patina of grease and engine oil.

"Hiya," she says, seeing River Song, "Who's this, Captain? We takin' on passengers? Simon can move into my bunk-"

"I _can_?"

"—I thought you'd want to—" Kaylee looks hurt. Simon's face, much to Mal and Jayne's amusement, is fighting between apology and anger that he's managed to somehow put his foot in his mouth, _again_. And he'd been doing so well, for almost two years.

"I just, uh, it's not that I don't want to, it's just that I'd really rather you asked me, first," said Simon. "And there's River to think of, as well…"

Eventually Kaylee will get tired of that excuse, River Song can tell already, though she doesn't yet know either Kaylee or Simon's names.

Mal eventually decides to put the good doctor out of his misery, and says, "Ain't no call for that yet, Doc, don't worry your pretty little head. We got room."

They are all silent for a moment thinking of whose room it is they have.

River Song can take no more of the tension. She's on an awkward footing, and she needs to know these people if she's going to manage here, to ever feel even a minimum of security. She smiles brightly and stretches out a hand to Kaylee, deciding that it would be politic to prevent Kaylee from feeling as though she might have even the slightest interest in the doctor. _This _doctor, anyhow.

"River Song," she says. "Nice to meet you."

"Kaywinnit Lee Frye, but you c'n call me Kaylee," says the mechanic, smiling sweetly. The newcomer has something like Inara's glamour, even though she's wearing a man's shirt and short pants and her hair is a mess. River Song, for her part, finds Kaylee instantly adorable, if a little saccharine. She hopes the girl will be bearable.

"Simon," Simon says, putting forth his own hand. "Hi."

"Hello," says River Song, biting back a _sweetie_. The goofy young doctor who says the wrong thing…the one comfort of her childhood, however occasional, the lust object of her adolescence. Okay, yeah, and now, too.

"Jayne," growls the merc, looking River up and down without the slightest hint of shame. She finds this refreshing, and returns the favor. Jayne grins. "Y'know," he says to Mal, "I like this passenger. Why can't we have ones like her all the time?"

Simon rolls his eyes. "Don't bother the human women, Jayne," he says.

"What? Then how'd I ever get—"

"Let's go look at the, uh, kitchen," says Mal, and Kaylee eagerly joins the tour and steers River Song by the elbow after the captain, chattering happily as she goes.

…

River Tam is flying solo. She is many things up here, alone. She is most of all herself because there is no one to tell her otherwise, no one to say her words aren't right the way they are, to look at her askance as she grins apropos of nothing they can see or hear. She is grinning now, looking out into the black, knees drawn up to her chest because it's easy flying for the moment and she's come to her delta, found another tributary of the great river, merged for the moment. They will diverge again, not too far in the future, of course. The melodious River must go back to her madman in his box, to her mother and father still searching all the time, though they know it's rare enough their girl can come home.

They look for her. They at least want her, whatever shape she comes in. Even if she shot the madman out of his box, it wasn't her fault, it wasn't her, Melody, it was the weapon instead.

River understands why the other changed her name. The need to be new, the reforging makes you another machine, gun gone to something less harmful. The need for a new word, because a new word has a new definition that is not theirs, and words are important, words can be weapons too. They called _her _River, in That Place, but so did Simon and her parents when she thought she was sure of their love. She wrote it neatly on the top of her pages of equations, saw it printed cleanly on awards and programs for dance recitals, sees it now below her photograph on a wanted bulletin on the Core. River Tam is who she was before and who she wants to be again, and she's not going to let them change her name, too, along with everything else they took.

But those people on that bright white ship, the terrifying woman with her half-sight looking over all, the soldiers and religion pervading the air, everything always war, and then that house like a nightmare, that house like River's tattered mind at the very beginning of her coming back, they were the only ones in the other River's memory who called her Melody, for a very long time.

She didn't hear music until she was ten.

This hurts River Tam, to think about the whole hole in the other girl's heart. It's larger than hers, the location different. Of course they didn't literally alter her heart (yes, she only has one, even distracted _her _guardian doctor would have noticed that). The nature of Time. A River in one direction, mostly; places you can't turn around, where the current is too strong; things that can't be changed despite the aching pull of every atom in a body.

And _music_. Stays inside your head and keeps you sane and her brother is sometimes too much like Victor Frankenstein (_what does that make her?_ _but she'd be that monster-mad if all she could find to read was Milton, anyway_) and locks himself up voluntarily, hiding.

Good that Kaylee's good at sifting through mechanical parts and finding human hearts.

River has a mental image of Kaylee collecting a trove of beating human hearts from Serenity's engine and laughs out loud.

"Somethin' funny, lil Albatross?"

The captain's leaning in the doorway, trying to look irate but half-smiling at her in spite of himself.

"Hearts in the engine," she says.

"That's what Kaylee would say."

"Yes. Are you angry?"

"About Miss Song or whatever her name is? A little. She reminds me in a powerful fashion of Saffron, and that ain't an adventure I'm in a hurry to repeat."

"Not like Saffron."

"You sure?"

Dramatic eyeroll. "_Yes_."

Mal heaves a sigh, equally dramatic. "Mind tellin' me what she _is _like, then? I wouldn't object to knowin' the _who_, either."

"Whom," says River. She doesn't need to look to know the face Mal's making, but that's not psychic or broken, just familiarity, and it feels warm as a quilt.

"Shut up."

"You want me to speak."

"Yeah, on the question I _asked_ you."

"Little girl lost, just like me. Parents fooled by the pretty doll, so lifelike. Even her father so good at watching didn't _see_. Has a doctor, too, watches over her, but she's afraid of her when she's near him. She knows things, like me, but doesn't hear them, lives them wrong, out of order. Her brain isn't broken but her mind is bent and her time is shattered in between five thousand years."

"Oh-kay…" he takes this in a moment. Doesn't seem too threatening, and the other girl's definitely not from the same cloth as this River. Way too lucid, normal-seeming. "Her name's her right name, and everything?"

"Complicated question." River Tam is grinning.

"She is who she says she is?"

"No one is who they say they are. Words are too simple. All of language wouldn't work to say a mind."

"You _know _what I mean, Albatross."

She smiles wider and ducks her head a little in acquiescence. "Yes. She is River Song. She has been a thief but not from us, she has been a weapon but not theirs, she will sift through the past forever and sing in an endless loop, because she took her turn with her doctor, too."

Mal has pretty much gotten lost in the woods of her words. "Not in a way Kaylee's gonna object to? I mean, that last part."

She rolls her eyes. "Different doctor, different turn. Saved her so she saved him. But she did that too. Not with Simon though."

"You vouch for her?"

"I will be her voucher, yes. I will be her security."

"Good enough for me."

"I knew it would be."

"Told you, stay outta my head."

"Didn't need to go in."

"Oh?"

"Captain," she turns her head toward him and she's grinning like an ordinary girl, brimming over with laughter at her own thoughts, thoughts she can make into words, "You gave me the order to take off three hours ago."

With the other River on board. Oh. "Oh," says Mal.

"Oh, yes," says River Tam, letting the echo loose from her mouth.


End file.
